Health calculators

Tyrer-Cuzick Calculator

Updated Jul 16, 2026 By Jehan Wadia
Rate Formulas Medical disclaimer
⚠ This is NOT the validated Tyrer-Cuzick (IBIS) clinical tool. The numbers shown by this page are generated by a simplified multiplicative relative-risk model and will diverge — sometimes substantially — from scores produced by the clinical Tyrer-Cuzick/IBIS pedigree algorithm. Do not use these estimates to make screening, surveillance, or chemoprevention decisions; those require a formal Tyrer-Cuzick assessment from a qualified healthcare professional or risk-assessment clinic. This tool is for general health awareness and educational purposes only.
About You
Model applies to ages 18–90.
Reproductive & Hormone History
Have you ever had a menstrual period?
Leave blank if unknown — do not enter 0.
Leave blank if unknown — do not enter 0.
Medical History & Breast Density
Prior breast biopsy / proliferative disease
Abnormal-looking but non-cancerous cells found on biopsy.
Abnormal cells in the milk lobules; a marker of higher risk.
Personal ovarian cancer history
BRCA1/2 are inherited genes that strongly raise breast-cancer risk.
Have you personally been diagnosed with breast cancer?
Family History
Mother, sisters, or daughters affected.
Grandmothers, aunts, half-sisters, nieces, cousins.
Your Inputs
Your Breast-Cancer Risk Estimate (simplified model — not a Tyrer-Cuzick/IBIS score)
Your 10-Year Risk
—
Average 10-Year Risk
—
Your Lifetime Risk (to 85)
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Average Lifetime Risk (to 85)
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Chance of remaining breast-cancer free (next 10 years)
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Risk Category (lifetime)
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MeasureYouAverage Woman (same age)
Category Thresholds (lifetime risk)
Below Average — under 12%
Average — 12% to 20%
Above Average — 20% to 30%
High — 30% to 50%
Very High — 50% and above
Risk Comparison
Lifetime Risk Gauge
Step-by-Step Solution

Introduction

The Tyrer-Cuzick model, also called the IBIS tool, is one of the most trusted ways to estimate a woman's chance of getting breast cancer. Doctors and clinics use it to decide if a patient needs extra screening, such as an MRI, or medicines that can help lower risk. The model looks at many parts of your health, including your age, weight, family history, hormone use, breast density, and whether you carry a BRCA gene mutation. It then combines all of these factors to give you a 10-year risk and a lifetime risk score. If you are looking for an alternative approach, our Breast Cancer Risk Calculator uses the Gail model framework for comparison.

This calculator uses a simplified version of that model. It applies known risk factors and multiplies them together to produce an estimate. It is not the validated clinical Tyrer-Cuzick/IBIS software and may give results that differ from the official tool. You should not use the numbers from this page to make medical decisions on your own. Instead, share your results with your doctor or visit a breast cancer risk clinic for a full assessment.

To get started, fill in each section below with your personal and family health details, then press Calculate. The tool will show your estimated risk, compare it to the average woman your age, and explain each step of the math behind your score.

How to Use Our Tyrer-Cuzick Calculator

Enter your personal health details, family history, and reproductive history below. The calculator will estimate your 10-year and lifetime breast cancer risk and compare it to the average woman your age.

Current Age: Enter your age in years. This tool works for ages 18 to 90. Use the plus and minus buttons or type your age directly. If you need to calculate your exact age from your date of birth, our Age Calculator can help.

Unit System: Choose Imperial (feet, inches, pounds) or Metric (meters, kilograms). The calculator will convert your numbers if you switch between the two.

Height and Weight: Enter your height and weight using your chosen unit system. The calculator uses these to find your BMI, which can affect breast cancer risk after menopause.

Have You Ever Had a Menstrual Period: Select Yes or No. If Yes, enter the age when your first period started. Leave the age blank if you do not remember.

Have You Given Birth to a Live Child: Select Yes, No, or Unknown. If Yes, enter your age when your first child was born. Leave the age blank if you do not remember.

Menopause Status: Select whether you are premenopausal, perimenopausal, postmenopausal, or unsure. If you are postmenopausal, enter the age when menopause began.

Hormone Replacement Therapy (HRT): Select whether you have never used HRT, stopped it 5 or more years ago, stopped it less than 5 years ago, or currently use it. If you recently stopped or currently use HRT, choose whether it is estrogen-only, combined, or unknown.

Prior Breast Biopsy: Select whether you have had no biopsy, a biopsy with unknown results, or a biopsy that showed hyperplasia without atypia. Check the box for atypical hyperplasia if abnormal but non-cancerous cells were found. Check the box for LCIS if lobular carcinoma in situ was found.

Breast Density: Choose how your breast density was measured. If you know your BI-RADS category (A through D), select it. If you have a density percentage from a VAS or Volpara report, enter that number. Choose Unknown if you have not had this measured.

Personal Ovarian Cancer History: Select Yes if you have been diagnosed with ovarian cancer. Otherwise select No.

Ashkenazi Jewish Heritage: Select Yes, No, or I don't know. This heritage is linked to higher rates of certain gene mutations that raise breast cancer risk.

BRCA Mutation Status: Select whether you have not been tested, tested negative, or tested positive for BRCA1 or BRCA2. These are inherited gene changes that strongly raise breast cancer risk.

Personal Breast Cancer Diagnosis: Select Yes if you have been diagnosed with breast cancer. This model is not designed for people with a prior diagnosis, so results should be read with caution.

First-Degree Relatives with Breast Cancer: Enter the number of mothers, sisters, or daughters who have had breast cancer. Enter 0 if none.

Second-Degree Relatives with Breast Cancer: Enter the number of grandmothers, aunts, half-sisters, nieces, or cousins who have had breast cancer. Enter 0 if none.

Additional Family Details: Check any boxes that apply — a relative diagnosed before age 50, a relative with cancer in both breasts, a relative with ovarian cancer, or a male relative with breast cancer. These details help refine your family history risk.

Calculate Button: Press "Calculate" to see your results. The tool will show your estimated 10-year risk, lifetime risk to age 85, chance of staying breast-cancer free, and a risk category. A bar chart and gauge chart will also appear to help you compare your risk to the average.

What Is the Tyrer-Cuzick Breast Cancer Risk Calculator?

The Tyrer-Cuzick model, also called the IBIS tool, is a way to estimate a woman's chance of getting breast cancer. It was created by doctors Jack Cuzick and Jonathan Tyrer. Unlike simpler models, it looks at a wide range of factors — including family history, hormones, body size, breast density, and genetics — to give a more complete picture of risk. You can also explore our Breast Cancer Risk Calculator for an estimate based on the Gail model, which uses a different set of inputs.

How Does It Work?

The calculator takes information you enter about your health and background. It then compares your risk factors against data from large studies of women over many years. The result is two main numbers: your 10-year risk (your chance of getting breast cancer in the next 10 years) and your lifetime risk (your chance from now until age 85). It also shows you how your numbers compare to an average woman of the same age. If you are interested in other health risk assessments, tools like the ASCVD Risk Calculator and the Framingham Risk Calculator use similar approaches to estimate cardiovascular disease risk.

What Factors Affect Your Risk?

Many things can raise or lower breast cancer risk. The main ones this tool considers are:

  • Age — Risk goes up as you get older.
  • Family history — Having a mother, sister, or daughter with breast cancer raises your risk. The more relatives affected, the higher the risk.
  • BRCA1 and BRCA2 genes — These inherited gene changes greatly increase the chance of breast cancer.
  • Breast density — Dense breast tissue makes cancer harder to spot and raises risk.
  • Hormone history — Starting periods early, going through menopause late, or using hormone replacement therapy (HRT) can increase risk. Women tracking their menstrual cycle may also find our Ovulation Calculator or Period Calculator helpful for general reproductive health awareness.
  • Body weight — A higher BMI after menopause is linked to higher risk. You can also use our Ideal Body Weight Calculator or Body Fat Calculator to learn more about your body composition.
  • Atypical hyperplasia or LCIS — These are abnormal cell changes found on a breast biopsy. They are not cancer, but they are strong risk markers.

What Do the Results Mean?

A lifetime risk under 15% is considered average. A lifetime risk of 20% or higher is often the point where doctors recommend extra screening, such as breast MRI along with a mammogram. A risk of 30% or more is considered high, and your doctor may discuss ways to lower it, such as medication or closer monitoring.

The tool also shows your chance of staying breast-cancer free over the next 10 years. For most women, this number is above 90%, which can be reassuring. For a broader view of health and longevity, you may also find our Life Expectancy Calculator informative.

Important Limitations

This online version uses a simplified model. It is not the same as a clinical Tyrer-Cuzick/IBIS assessment run by a doctor or genetic counselor. The real tool uses a detailed family tree (pedigree) and more complex math. Results from this page may differ from a clinical score. Do not use this tool to make medical decisions. Always talk to a healthcare professional about your personal breast cancer risk and what screening plan is right for you. Taking care of your overall health — including monitoring your calorie intake, staying physically active, and keeping a healthy BMI — can also play a role in reducing your risk.

Formulas used

Body Mass Index (BMI)
\text{BMI} = \frac{w}{h^{2}}
Combined Relative Risk
RR = \prod_{i=1}^{n} RR_i \quad \text{clamped to } [0.3,\;12]
Adjusted Cumulative Incidence
F_p(x) = 1 - \bigl(1 - F(x)\bigr)^{RR}
10-Year Risk
R_{10} = \frac{F_p(a+10) - F_p(a)}{1 - F_p(a)}
Lifetime Risk (to age 85)
R_{\text{life}} = \frac{F_p(85) - F_p(a)}{1 - F_p(a)}
Probability of Remaining Breast-Cancer Free (10 yr)
P_{\text{free}} = 1 - R_{10}

Frequently asked questions

What is a good Tyrer-Cuzick score?

A lifetime risk under 15% is considered average. A score between 15% and 20% is slightly above average. A score of 20% or higher usually means your doctor will suggest extra screening like a breast MRI. A score of 30% or above is high risk, and your doctor may talk about medicines or closer monitoring to help lower it.

How accurate is this online calculator compared to the real Tyrer-Cuzick tool?

This calculator uses a simplified model that multiplies known risk factors together. The real clinical Tyrer-Cuzick/IBIS software uses a detailed family tree and more complex math. Results from this page can differ from the official tool, sometimes by a meaningful amount. Use this for general awareness only, and see a doctor or risk clinic for an official score.

Can men use this calculator?

No. This tool is built for women only. It uses factors like menstrual history, menopause age, and pregnancy history that do not apply to men. Male breast cancer is rare and needs a different type of risk assessment. If you are a man concerned about breast cancer, talk to your doctor.

What is the difference between 10-year risk and lifetime risk?

Your 10-year risk is your chance of getting breast cancer in the next 10 years from your current age. Your lifetime risk is your chance of getting breast cancer from now until age 85. Lifetime risk is almost always a higher number because it covers a much longer time period.

What does breast density mean and why does it matter?

Breast density describes how much fibrous and glandular tissue you have compared to fatty tissue. Dense breasts have more of this tissue. Dense breasts raise breast cancer risk and make tumors harder to see on a mammogram. Your density is measured during a mammogram and reported as a BI-RADS category from A (mostly fatty) to D (extremely dense).

What if I do not know my breast density?

Select "Unknown" from the breast density dropdown. The calculator will treat density as neutral and not add or subtract risk for it. For a more complete result, ask your doctor for your BI-RADS category from your most recent mammogram.

What is atypical hyperplasia?

Atypical hyperplasia means abnormal-looking cells were found in your breast tissue during a biopsy. These cells are not cancer, but they are a strong marker that your risk of breast cancer is higher than average. If you have been told you have this condition, check the atypical hyperplasia box in the calculator.

What is LCIS?

LCIS stands for lobular carcinoma in situ. It means abnormal cells were found in the milk-producing lobules of your breast. LCIS is not breast cancer, but it is a risk marker. Having LCIS means you have a higher chance of developing breast cancer in either breast in the future.

Should I get tested for BRCA mutations?

Not everyone needs BRCA testing. It is usually recommended if you have a strong family history of breast or ovarian cancer, a relative who tested positive for BRCA, Ashkenazi Jewish heritage, or a personal history of breast or ovarian cancer at a young age. Talk to your doctor or a genetic counselor to see if testing is right for you.

Why does the calculator ask about Ashkenazi Jewish heritage?

People of Ashkenazi Jewish descent have a higher rate of BRCA1 and BRCA2 gene mutations compared to the general population. About 1 in 40 Ashkenazi Jewish individuals carry one of these mutations, compared to about 1 in 400 in the general population. This raises the average breast cancer risk for this group.

Does hormone replacement therapy (HRT) raise breast cancer risk?

Yes. Combined HRT (estrogen plus progestogen) raises risk the most. Estrogen-only HRT raises risk by a smaller amount. Risk goes up the longer you use HRT. After you stop, the extra risk starts to go down but may take several years to return to normal. The calculator accounts for whether you currently use HRT, recently stopped, or stopped more than 5 years ago.

What if I have already had breast cancer?

This model is not designed for people who have already been diagnosed with breast cancer. If you select "Yes" for a prior diagnosis, the calculator will show a warning. The results should be read with caution and are not reliable for someone with a personal history of the disease. Talk to your oncologist about your specific recurrence risk.

How does BMI affect my breast cancer risk?

A higher BMI raises breast cancer risk mainly after menopause. Extra body fat increases estrogen levels, which can fuel certain types of breast cancer. Before menopause, the link between BMI and breast cancer risk is weaker and more complex. The calculator only applies a BMI risk factor if you are postmenopausal.

Why does early menstruation raise risk?

Starting your period at a younger age means your body is exposed to estrogen for more years over your lifetime. This longer exposure gives breast cells more time to be affected by the hormone, which can raise the chance of cancer developing. The calculator increases your risk slightly if your first period started before age 13.

Does having children lower breast cancer risk?

Yes, in general. Women who have given birth to at least one child have a slightly lower risk than women who have not. Having your first child at a younger age lowers risk even more. The calculator adds a small amount of extra risk if you have never had a live birth or had your first child after age 30.

What do first-degree and second-degree relatives mean?

First-degree relatives are your mother, sisters, and daughters. They share about 50% of your genes. Second-degree relatives include grandmothers, aunts, half-sisters, nieces, and cousins. They share about 25% of your genes. Breast cancer in first-degree relatives raises your risk more than in second-degree relatives.

Is my data saved or shared when I use this calculator?

No. All calculations happen in your web browser. Your health information is not sent to any server, stored in any database, or shared with anyone. When you close the page, your inputs are gone.

What should I do if my risk score is high?

Do not panic. A high score does not mean you will get breast cancer. It means your chance is higher than average. Talk to your doctor about your results. They may suggest extra screening such as breast MRI, genetic counseling, or risk-reducing medicines. Early detection greatly improves outcomes.

How often should I recalculate my risk?

Your risk can change over time as you age, go through menopause, start or stop HRT, or learn new family history. It is a good idea to recalculate every 1 to 2 years or whenever a major health change happens. Always share updated results with your doctor.

What does the chance of staying breast-cancer free mean?

This number is simply 100% minus your 10-year risk. If your 10-year risk is 5%, your chance of staying breast-cancer free over the next 10 years is 95%. For most women, this number is above 90%, which means the odds are strongly in your favor.

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Estimate 5-year and lifetime breast cancer risk using the Gail model with Tyrer-Cuzick adjustments. Enter age, family history, density, and biopsy results.

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